Half to joseph brodie smith



(No Model.) 2 Sheets-Sheet 1.' A. L. ULOUGH.

COMBINED SYSTEM OF ALTERNATING AND DIRECT CURRENT DISTRIBUTION.

Patented Oct. 2, 1894 WI EEEEE'.

(No Model.) 2 Sheets- Sheet 2;

A. L. OLOUGH.

COMBINED SYSTEM OF ALTBRNATING AND DIRECT CURRENT DISTRIBUTION. No.526,992. Patented Oct. 2, 1894.

Wt t

'm: mums PEI'CRS c0.. pnorcuurwu, WASMINOYON, mo.

UNrrED STATES PATENT Orrrcn.

ALBERT L. OLOUGH, OF MANCHESTER, NEW HAMPSHIRE, ASSIGNOR OF ONE A HALFTO JOSEPH BRODIE SMITH, OF SAME PLACE.

COMBINED SYSTEM OF ALTERNATING AND DIRECT CURRENT DISTRIBUTION.

1FECIFIGATION forming part of Letters Patent No. 526,992,'dated October2, 1894. Application filed May 15, 1894. Serial N... 511,289. (Nomodel.)

To all whom it may concern:

Be it known that I, ALBERT L. CLOUGH, a citizen of the United States,and a resident of Manchester, in the county of Hillsborough and State ofNew Hampshire, have invented new and usefullmprovements in a CombinedSystem of Alternate and Direct OurrentDistribution, of which thefollowing, taken in connection with the accompanying drawings, is aspecification.

This invention relates to improvements in electrical distribution and itconsists in a combined system of alternate and direct electric currentdistribution adapted for use in connection with electric lamps or othertranslating devices, and it has for its object to obviate the losseswhich are met with in the ordinary methods of supply. This is attainedby the use of a combination of both the alternating and direct currentas will hereinafter be more fully shown and described reference beinghad to the accompanying drawings which represents a diagram of theimproved systemof current distribution.

In supplying electrical energy by the alternating current system, aconstant loss is experienced, due to the hysteresis and eddy currents inthe iron of the transformers which are employed. This loss takes placeno matter whether there are many or few lights in operation, and amountsat all times to a considerable fraction of the total transformercapacity connected. While this loss is not particularly serious at timeswhen a large amount of energy is being distributed, it becomes so duringperiods when the call or current is small, amounting at such times toseveral times the useful energy sent out. It is to do away with thisloss during light loads by the use of direct current during the period,that the following method is devised.

Although the method makes use of a pair of extra wires for the supply ofthe direct currentthe amount of current called for during the time whenthey are in use is so inconsiderable that their cross section need bebut small.

The advantage of this system is that the interest on the added amount ofcopper which itis necessary to install, is but a small part I only ofthe saving in energy which should be brought about by the prevention ofthe constant transformer losses during a large part of the time.

In the drawings-Figure 1 represents the apparatus arranged not only toshort-circuit but to absolutely disconnect the branch from 'the systemas a Whole. 'rangement designed simply to short-circuit Fig. 2 shows anarthe branch without disconnecting it from the rest of the system.

Referring to Fig. 1:D D are sources respectively of direct andalternating current,

and M and M are the respective mains leading from them to the consumersstations A, B.

T T represent the transformers of the two stations of which P P are theprimaries, connected to the alternating mains and S S are thesecondaries. The transformer secondary :of each station is insertedintoone side of the branch leading from the direct current mains use; but toremain open at all other times so as not to short circuit the directcurrent mains when the direct current is on them.

The short circuiting devices shown are of the automatic variety, andeach is so arranged as to not only short-circuit the particular branchin which it is placed,butto absolutely disconnect said branch from therest of the system. This is accomplished by means of the alternatingcurrent'acting upon repulsion devices H H which consist of therespective electro-magnets I l provided with conducting go cylinders K Kfitting freely about them, the induced currents in said cylinders beingrepolled by the electro-magnets. The cylinders are suitably connected tothe respective levers O, R, O R which carry the contacts 9 5 which,co-operating with the fixed contacts, accomplish the short circuitingand disconnection by means of the arrangement of connections shown. Therepulsion devices are not capable of being operated by direct currentIco mains in the usual manner.

and so the levers and movable contacts are constantly held in theposition shown, by the action of the respective springs Q Q as long asthe direct current is in use, giving the branch a connection to thedirect current \Vhen however the alternating current is applied, therepulsion device acts and overcomes the spring, the lever and itscontacts move to the opposite position and the short circuiting anddisconnection are accomplished.

It is not necessary, although it may be advisable thata short circuitingdevice he placed in each branch, as such devices distributed upon themain conductors at convenient points might be preferable and it is notnecessary although it may be desirable that the devices disconnect aswell as short circuit the branches. Their function may simply be toshort circuit and thus forma return path for the alternating currents,without separating the branch from the rest of the system and they maybe operated by hand or any other means.

Theapparatus is shown in Fig. 2 in the condition in which it wouldremain while the direct current is in use. Upon the application of thealternating current, however, the repulsion device K would act, raisingthe pivoted lever 0 into contact with the fixed contact L, therebyaffecting the short-circuit through the path as shown, as long as the alternating current is applied, the short-circuit being broken by theaction of spring Q as soon as the alternating current ceases and theapparatus remaining unaffected by the direct current.

It is designed to connect the transformers in such a way that about thesame number will be poled in, each direction on the mains M thusreducing the current flowing in them even perhaps to the extent of doingaway with most or all of the short circuiting devices. As anillustration of this method of poling the transformers, reference may behad to Fig. l, where the two transformers T and T are seen to have theircorresponding primary wires connected to the same primary mains. Theircorresponding secondary wires are therefore of the same instantaneouspolarity, but they are shown necessarily connected to the mains M, M,the wire 1 of T going to one of the direct current mains while the wire2 of T goes to the other direct current main. These two transformers maybe regarded as the representatives of the two groups into which all thetransformers of the system would be divided, each group to have, asnearly as possible, the same capacity.

In the application of this system the alternating current would be inuse and the direct current cut off, during the period of heavy loadwhich usually takes place in the evening. The alternating system wouldthen be operating at its maximum efiiciency while the heaviness of theload at this time would preclude the use of the direct current systemowing to the large size of the mains which would be required to operateat the low voltage used on the transformer secondaries. During the lightloads of the rest of the day the direct current would be in use and thealternating current cut off, thereby avoiding the large transformer losswhich would otherwise take place, while the small call for current whichis experienced during these portions of the day would allow the use ofquite small direct current mains without too great loss.

For the purpose of changing the current from the alternating to thedirect source or vice versa I employ a suitable switch N adapted toestablish communication from the direct source D to the main M by meansof the contacts m, m, as shown in the drawings, or from the alternatingsource D to the main M by means of the contacts m m when the switch isturned in an opposite direction as may be required during the working ofthe system as above mentioned.

\Vhat I wish to secure by Letters Patent and claim is- The combinationof a source of direct and of alternating currents of conductors for thedistribution of said currents, of branches to connect the translatingdevices to the direct current mains, of transformers having theirprimaries connected to the alternating current mains, and each havingits secondary included in one side ofits appropriate branch, and ofdevices to short circuit said direct current mains when the alternatingcurrent is on and to remove the short circuit when the alternatingcurrent is off, substantially as set forth.

In testimony whereof I have signed my name to this specification, in thepresence of two subscribing witnesses, on this 28th day of April, A. D.1894.

ALBERT L. CLO UGll.

lVitnesses:

ALBAN ANDREN, KITTIE M. HANSON.

